1. Field of the Invention
The present invention relates to a hemostatic dressing that comprises a plurality of layers that contain resorbable materials and/or coagulation proteins. The hemostatic dressing is useful for the treatment of wounded tissue.
2. Background of the Invention
The control of hemorrhage (bleeding) is a critical step in first aid and field trauma care. Unfortunately, the occurrence of excessive bleeding or fatal hemorrhage from an accessible site is not uncommon. J. M. Rocko et al, J. Trauma 22:635 (1982). Mortality data from Vietnam indicates that 10% of combat deaths were due to uncontrolled extremity hemorrhage. SAS/STAT Users Guide, 4th ed. (Cary, N.C.: SAS Institute Inc; 1990). Up to one third of the deaths from exsanguination during the Vietnam War could have been prevented by the use of effective field hemorrhage control methods. SAS/STAT Users Guide, 4th ed. (Cary, N.C.: SAS Institute Inc; 1990).
Although civilian trauma mortality statistics do not provide exact numbers for prehospital deaths from extremity hemorrhage, case and anecdotal reports indicate similar occurrences. J. M. Rocko et al., J. Trauma 22:635 (1982). These data suggest that a substantial increase in survival can be effected by the prehospital use of a simple and effective method of hemorrhage control.
Liquid fibrin sealants have been used as an operating room adjunct to hemorrhage control. J. L. Garza et al., J. Trauma 30:512-513 (1990); H. B. Kram et al., J. Trauma 30:91-101 (1990); M. G. Ochsner et al., J. Trauma 50:884-887 (1990); T. L. Matthew et al., Ann. Thorac. Surg. 50:40-44 (1990); H. Jakob et al., J. Vasc. Surg., 1:171-180 (1984). The widespread use of fibrinogen and thrombin was common in the last year of World War π, but was abandoned because of the transmission of hepatitis. D. B. Kendrick, Blood Program in WW II (Washington, D.C.: Office of the Surgeon General, Department of Army; 1989), 363-368.
Single donor fibrin sealants have been widely used clinically, not only for hemorrhage control but in various surgical situations. W. D. Spotnitz, Thromb. Haemost. 74:482-485 (1995); R. Lerner et al., Surg. Res. 48: 165-181 (1990). The American Red Cross and others have developed plasma protein purification methods that seem to eliminate the hepatitis risk. Reiss et al., Trans. Med. Rev. 70:85-92 (1996).
A dry fibrinogen-thrombin dressing (TACHOCOMB™, Hafslund Nycomed Pharma, Linz, Austria) is also available for operating room use in many European countries. Schiele et al., Clin. Materials 9:169-177 (1992). Present formulations of this dressing use bovine thrombin. While this fibrinogen-thrombin dressing requires no premixing and is easy to use, its utility is limited by a requirement for storage at 4° C. and the necessity for prewetting with saline solution prior to application to the wound.
A hemostatic sandwich dressing has been described, which contains a layer of thrombin sandwiched between layers of fibrinogen (see, e.g., PCT/US99/10952, which is incorporated herein by reference). Although such dressings can be used in methods for treating wounded tissue, such conventional sandwich dressings can become delaminated, whereby the edges of the layers of the dressing no longer adhere to each other. Such delamination can result in reduced interaction of the dressing components layers, with decreased effectiveness of the dressing in preventing hemorrhage.